Collaborative Research: Characterization and Optimization of N-Heterocyclic Carbene Functionalized Nanoparticle Systems

在化学系大分子、超分子和纳米化学项目的支持下，田纳西大学的David Jenkins博士和圣母大学的Jon Camden博士和Gina Nvoa Svarovsky博士探索了利用N-杂环卡宾(NHCS)化学对金纳米颗粒进行表面修饰。金纳米粒子通常由带电分子如柠檬酸盐或带有硫醇锚定基团的单分子层稳定，被广泛应用于化学、生物和环境技术中，但由于纳米粒子在水中固有的不稳定性，其使用受到限制。詹金斯博士和卡姆登博士正在寻找通过使用NHC配体来克服这一限制的方法。为了做到这一点，他们使用了一种自上而下的方法，即在将金属离子转移到金纳米颗粒表面之前，首先将这些配体配位来创造金属离子。他们正在使用各种表征工具来评估这种化学，并更好地了解哪些NHC配体有助于增强功能化金纳米颗粒的稳定性。Jenkins博士、Camden博士和Svarovsky博士正在进行一项教学研究员常驻计划，以在研究实验室创造身临其境的研究体验，以及一项让中学生参与真实科学(SEA)计划，该计划涉及到金属NHC络合物的合成、表征和转移到金纳米颗粒表面，表征所产生的NHC配体在金纳米颗粒上的键合和紧密堆积，以及随后对NHC功能化的金的稳定性和寿命的评估。所有这些研究都采用了自上而下的方法，其中金纳米颗粒在孤立的硬币金属NHC络合物在溶液中形成后被功能化。这一通用的、自上而下的策略预计将广泛适用于各种形状和大小的金纳米粒子。这种方法有可能克服与自下而上功能化步骤相关的限制，在这些步骤中，每个单独的反应通常针对特定的系统进行优化。使用杂环卡宾功能化的金纳米粒子有望克服传统表面化学所面临的挑战。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

With the support of the Macromolecular, Supramolecular, and Nanochemistry Program in the Division of Chemistry, Dr. David Jenkins of the University of Tennessee and Drs. Jon Camden and Gina Navoa Svarovsky of the University of Notre Dame explore the use of N-heterocyclic carbenes (NHCs) chemistry for the surface modification of gold nanoparticles. Gold nanoparticles, which are typically stabilized by charged molecules such as citrate or monolayers with thiol anchoring groups, are used in wide-ranging chemical, biological, and environmental technologies but use is limited by the inherent instability of the nanoparticles in water. Drs. Jenkins and Camden are identifying ways to overcome this limitation by using NHC ligands. To do so, they are using a top-down method that involves the initial coordination of these ligands to coinage metal ions before being transferred to gold nanoparticle surfaces. They are using a variety of characterization tools to evaluate this chemistry and to better understand what NHC ligands promote enhanced stability of the functionalized gold nanoparticles. Drs. Jenkins, Camden, and Svarovsky are pursuing a Teaching Fellows Residency program to create an immersive research experience in the research laboratories and a Student Engagement in Authentic Science (SEAS) program that engages middle school students with original scientific data.The research involves the synthesis, characterization, and transfer of metal NHC complexes to gold nanoparticle surfaces, the characterization of the resulting bonding and close packing of a library of NHC ligands on gold nanoparticles, and the subsequent evaluation of NHC-functionalized gold stability and longevity. All of these studies utilize a top-down approach wherein the gold nanoparticles are functionalized after isolated coinage metal NHC complexes have formed in solution. This universal, top-down strategy is expected to be broadly applicable to gold nanoparticles of varying shapes and sizes. This approach has the potential to overcome limitations associated with bottom-up functionalization steps where each individual reaction is typically optimized for a specific system. Gold nanoparticles functionalized with heterocyclic carbenes hold promise in the quest to overcome challenges faced by conventional surface chemistries.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.